U.S. Pat. No. 3,645,992, incorporated by reference herein in its entirety, discloses homogeneous linear ethylene olefin copolymers prepared using a soluble vanadium catalyst. Therein, homogeneous copolymers are defined as polymers in which the comonomer is randomly distributed within a given molecule, and in which all copolymer molecules have the same ethylene to copolymer ratio. The disclosed homogeneous copolymers have a moderately high molecular weight. For instance, as set forth in the Examples, the homogeneous copolymers have a melt index, as measured in accordance with ASTM D-1238, of from less than 0.1 to less than 25 g/10 min.
U.S. Pat. Nos. 5,272,236 and 5,278,272, incorporated by reference herein in their entirety, disclose substantially linear ethylene olefin copolymers prepared using a single site polymerization catalyst. The disclosed substantially linear copolymers are characterized as having from about 0.01 to about 3 long chain branches per 1000 carbons. Unlike the homogeneous copolymers of Elston, the disclosed substantially linear copolymers are characterized by a molecular weight distribution (M.sub.w /M.sub.n) which is independent of the I.sub.10 /I.sub.2, as measured in accordance with ASTM D-1238.
Pourable ultra-low molecular weight ethylene polymers for use as oil additives are known in the art. For instance, PCT published application 94/12193 discloses ethylene/butene copolymers having a number average molecular weight between 1500 and 7500 prepared using a biscyclopentadienyl metallocene catalyst. Such polymers are said to exhibit a pour point of -30.degree. C. or less, as determined by ASTM Method No. D97. As set forth in the published application, polymers exhibiting such low pour points do not adversely affect the pour point of a lubricant to which they are added.
Non-pourable ethylene polymers having a narrow molecular weight distribution, i.e., an M.sub.w /M.sub.n less than 2.5, and an ultra-low molecular weight, as evidenced by a number average molecular weight (Mn) of no more than 11,000, have been heretofore unknown. Industry would find advantage in such polymers for use in adhesive formulations, and as wax substitutes, ink modifiers, oil modifiers, viscosity modifiers, fibers, processing aids, sealants, caulks, etc.